ASPECt
Energy: Forms, Transformation, Transfer, and Conservation
Item RG184001: When an instant cold pack is used, energy is taken in because the temperature of the surroundings decreases.
Cold packs are commonly used to treat athletic injuries. A cold pack contains two chambers. One is filled with water and the other is filled with salt. When the cold pack is squeezed, the chamber containing the salt breaks open, which allows the salt and the water to mix inside the cold pack. As the salt and water mix, the salt dissolves and the temperature of the cold pack decreases.
As the salt dissolves, is energy being released to the surroundings or taken in from the surroundings and why?
- Energy is released because the temperature of the surroundings decreases.
- Energy is released because energy is released whenever a substance dissolves.
- Energy is taken in because the temperature of the surroundings decreases.
- Energy is neither taken in nor released because energy changes do not occur when substances dissolve.
- Distribution of Responses
- Scale Score for Item Difficulty
(200[Easy]-800[Difficult]) - 531
- Students Responding Correctly
| Group | Correct | Total | Percent |
|---|---|---|---|
| Overall | 964 | 3579 | 27% |
| Grades | |||
| 4–5 | 157 | 688 | 23% |
| 6–8 | 373 | 1466 | 25% |
| 9–12 | 434 | 1425 | 30% |
| Gender | |||
| Male | 457 | 1615 | 28% |
| Female | 475 | 1862 | 26% |
| Primary Language | |||
| English | 860 | 3208 | 27% |
| Other | 77 | 268 | 29% |
- Disciplinary Core Ideas
- PS1.B Some chemical reactions release energy, others store energy.